Journal of Hydrodynamics, Год журнала: 2024, Номер 36(4), С. 757 - 771
Опубликована: Авг. 1, 2024
Язык: Английский
International Journal of River Basin Management, Год журнала: 2022, Номер 21(4), С. 607 - 616
Опубликована: Апрель 10, 2022
Culverts are used to allow runoff pass through roads, railways, and embankments. Accumulation of debris during flood events reduces the culvert flow capacity hence overtopping results in failure both hydraulically structurally. This paper presents an experimental study temporal variations blockage upstream culverts due woody under unsteady conditions. To simulate conditions, a synthetic hydrograph was produced laboratory. Cylindrical wooden dowels with two different diameters were carrying events. Two shapes including box circular pipe examined here. The showed that maximum percentage occurs falling limb hydrograph. Although feeding rate smaller diameter into is considerable importance blockage, not influenced by large debris. It also found more susceptible than box-shaped culvert. Using regression analysis, predictive equations suggested estimate
Язык: Английский
Процитировано
20
Water Resources Research, Год журнала: 2023, Номер 59(3)
Опубликована: Фев. 23, 2023
Abstract Logjams in a stream create backwater conditions and locally force water to flow through the streambed, creating zones of transient storage within surface subsurface stream. We investigate relative importance logjam distribution density, permeability, discharge on simplified experimental channel. use physical flume experiments which we inject salt tracer, monitor fluid conductivity breakthrough curves water, determine breakthrough‐curve skewness characterize storage. then develop companion numerical model HydroGeoSphere reveal paths (or hyporheic zone) that contribute some longest transient‐storage timescales. In both simulations, observe formation an increase exchange at logjams. Observed complexities behavior depend largely zone. As expected, multiple successive logjams provide more pervasive by distributing head drop each jam, leading distributed but shallow paths. Decreasing permeability or increasing facilitate greater volumetric rate exchange. Understanding how characteristics affect solute transport channel zone has important management implications for rivers forested, historically environments.
Язык: Английский
Процитировано
12
Water Resources Research, Год журнала: 2024, Номер 60(3)
Опубликована: Март 1, 2024
Abstract Fallen trees enter the adjacent stream and are carried away downstream by current. As joins another one, complex hydrodynamics near their confluence make movement of wood hard to predict. These woods may accumulate resulting in backwater subsequent potential flooding. A laboratory study was conducted investigate accumulation behavior individual pieces confluence. The characteristics (i.e., length, diameter, density) hydraulic conditions discharge ratio release distance) were varied this investigation. It found that wooden released from tributary got occasionally trapped flow separation zone confluence, whereupon they mainly a clockwise vortex continued stay driven reverse cluster currents within zone. probability related its distance. effect diameter density tested parameters negligible. increased with an increase as well decrease longer had higher being trapped, whereas for those exceeding some critical value, nearly same, or dropped sharply. generalized model developed practical application. findings carry significant implications river management, particularly preventing risk flooding caused blockage.
Язык: Английский
Процитировано
5
Geomorphology, Год журнала: 2024, Номер 452, С. 109114 - 109114
Опубликована: Фев. 27, 2024
Язык: Английский
Процитировано
4
Earth Surface Processes and Landforms, Год журнала: 2025, Номер 50(6)
Опубликована: Май 1, 2025
Abstract Purposely placed in‐stream wooden leaky barriers (LBs) with lower gaps to facilitate flow during average conditions have become a popular type of nature‐based intervention in catchments for flood risk mitigation. Empirical evidence on their effectiveness remains rare, however. The hydro‐geomorphic effects 16 LBs were monitored over three years the Elm Sike, small upland stream (catchment area: 0.33 km 2 ) Scottish Borders, UK. aims structures to: (1) increase water storage and roughness and, turn, attenuate delay peaks; (2) trap store coarse sediment reduce sediment‐related problems downstream. Annual topographical surveys conducted assess geomorphic changes, continuous 5‐minute levels recorded changes peak travel times. Two‐dimensional hydraulic modelling (HEC‐RAS 2D) was undertaken impact changes. had no effect time rate stage rise or fall based 22 events an Exceedance Probability (AEP) ≥ 3.7%. Hydraulic showed limited velocity reduction expansion inundation extent due 50% AEP flows, but slightly greater larger 5% flows. However, increased velocities decreased more significantly morphological initiated by structures. hydrological impacts related size structures, close spacing steep, confined valley setting that capacity. At end three‐year period, reach‐wide net deposition response 3.49 ± 0.36 m 3 5.3% loss total LB backwater observed, local spatially variable. Backwater capacity at 10 reduced, gap eight bed scour, indicating accelerated underflow. Multivariable analysis height change inversely shear stress, channel cross‐section area slope. No factors explained deposition, threshold ≤0.4 initiating evident. These observations implications design placement river restoration management projects.
Язык: Английский
Процитировано
0
E3S Web of Conferences, Год журнала: 2023, Номер 415, С. 05031 - 05031
Опубликована: Янв. 1, 2023
Bridge clogging due to a debris flow is phenomenon scarcely studied but critical in hazard mapping the mountain area. Since rational and systematic approach still missing, we propose practical method deal with this numerical framework. We tested methodology by using, as model, two-phase, mobile-bed model TRENT2D and, site test case, village of Voueces north-west part Italian Alps. The application shows reasonable results highlights importance approach.
Язык: Английский
Процитировано
8
River Research and Applications, Год журнала: 2024, Номер 40(8), С. 1626 - 1641
Опубликована: Июнь 18, 2024
Abstract Recognition of the important physical and ecological roles played by large wood in channels on floodplains has grown substantially during recent decades. Although continues to be routinely removed from many river corridors worldwide, practice reintroduction spread across United States, Kingdom western Europe, Australia, New Zealand. The state‐of‐science regarding working with rivers was discussed a workshop held Colorado, USA, September 2022 40 participants who are scientists practitioners UK, Japan. objectives this paper present findings workshop; summarize two case studies restoration States; provide suggestions for advancing management. We results based participant judgements recommendations respect to: (i) limitations key barriers using wood, which reflect perceptions practicalities; (ii) gaps use management; (iii) scenarios is generally used effectively; (iv) not effectively. illustrate importance local geomorphic context, configuration complexity potential modification corridor morphology enhance desired benefits. Moving forward, we stress collaboration disciplines communities research scientists, practitioners, regulators, stakeholders; accounting stakeholder wood; increasing non‐scientist access latest knowledge.
Язык: Английский
Процитировано
3
Earth Surface Processes and Landforms, Год журнала: 2021, Номер 47(1), С. 32 - 57
Опубликована: Июнь 30, 2021
Abstract In the last 30 years, work on large wood (LW) has expanded and matured considerably, river scientists, managers practitioners now have a better appreciation of role LW in maintaining ecosystems, forming or stabilizing riverine landforms, interacting with morphodynamics. We gained understanding hazards posed by recruitment transport channel associated infrastructure. While dynamics traditionally been studied natural environment, innovations laboratory techniques enabled important advances process dynamics, using physical scale models, new sensors, scanners sophisticated model boundary conditions. Current trends research focus (1) mobilization logs, (2) trapping deposition sediment presence (3) contribution to hydraulic flow resistance. Ultimately, combined is needed assess impacts upon infrastructure erodible boundaries, such as bridge piers retention racks. this review, we present critical analysis emerging experimental obtained through modelling studies. put recent context global management challenges. particular, set our environmental engineering issues that confront catchment resource Switzerland New Zealand. show how improved models incorporating transport, accumulation scouring processes are contribute more reliable hazard risk assessment LW‐prone systems.
Язык: Английский
Процитировано
18
Water Resources Research, Год журнала: 2023, Номер 59(11)
Опубликована: Ноя. 1, 2023
Abstract In‐stream wood structures, such as single logs, river steps, and debris dams, are known to drive hyporheic flow, defined the flow that goes into subsurface region then back free‐flowing surface water. The plays an important role in regulating water quality biogeochemical cycles rivers. Here, we investigated impact of a channel‐spanning porous log jam, representing piles on through combination direct visualization theories. Specifically, developed method using refractive index‐matched sediment directly visualize around below formed by cylindrical rods, laboratory flume. We tracked velocity fluorescent dye moving transparent underneath jam. In addition, measured profile spatially varying near Our results show normalized jam‐induced flux remained smaller than 10% at Froude numbers () 0.06 increased factor five with increasing . combined mass momentum conservation equations Darcy's equation explain dependency Further, observed , dropped noticeably turbulent kinetic energy immediately downstream side These findings will facilitate future quantification caused jams.
Язык: Английский
Процитировано
7
Water Resources Research, Год журнала: 2022, Номер 58(5)
Опубликована: Май 1, 2022
Abstract Large wood (LW) can be transported along a river during floods, increasing flood‐associated hazards, particularly when it accumulates at river‐spanning infrastructures such as bridges and weirs. While most flume studies have explored LW movement with simple wooden elements (dowels), only few used more complex geometries, rootwads, under unsteady flow conditions. Quantitative assessment of interactions amongst has rarely been attempted the effect this additional complication even ignored, in both field laboratory studies. In study, experiments were conducted to assess rootwads on local scour deposition mobile gravel‐bed. The experiment was conditions, constricted segment reach, recreating conditions accumulations blockage. Results revealed that tends generate stable than without leading formation porous loosely packed accumulations. initial set experiments, patterns quite variable, but average, showed spatially extensive disturbance bed. led development pits reached bottom quickly rootwads. mean accumulated bedload volumes similar magnitude overall, however, highlighting many contingencies chain processes between dam resultant bed scour.
Язык: Английский
Процитировано
11